The general legal term for joint ownership of property is "concurrent ownership" or "concurrent estate." Under traditional common law, there are three types of concurrent ownership, two of which are in particularly widespread use today. State laws, however, may modify the rights and obligations of these various types of joint ownership.
Joint Tenancy Rights
Joint tenants own undivided interests in property. That means each tenant has the right to use and possess every aspect of the property. A joint tenant who pays taxes or a mortgage on the property has the right to receive compensation from other joint tenants in proportion to their share of ownership. Conversely, a joint tenant who exploits a feature of the property, diminishing its value, or who rents a portion of the property, can be forced to compensate the other joint tenants in proportion to their ownership interests.
Joint Tenancy Termination
A joint tenancy can end in a variety of ways. If any joint tenant sells his interest in the property, the buyer does not become a joint tenant, but a tenant in common with the seller's now severed portion of the property. The remaining original owners remain joint tenants with respect to the rest. If a joint tenant prevents another joint tenant from accessing or using part of the property, this ouster can also sever the joint tenancy. Upon severance, no matter what the cause, any joint tenant can demand compensation for repairs and upkeep or any outstanding rents or income owed.
Tenancy in Common
The most frequent type of concurrent ownership of property is called tenancy in common. Here, each owner has an interest in a distinct part of the property as well as the right to access and use the whole. Each tenant is liable to the others if they diminish the value of the property. Unlike a joint tenancy, an interest held as a tenancy in common can be devised in a will to a successor.
Termination of Tenancy in Common
The sale of one tenant in common's interest does not alter the arrangement between the remaining owners. A tenancy in common can be terminated, however, by a sale of the entire property to a single new owner, or by a co-tenant purchasing the other tenant's shares. When a tenancy in common is terminated, any tenant that made improvements to the property can receive compensation from the other tenants, or bear the liability of any diminution in value.
Tenancy by the Entirety
Fewer than half of the 50 states recognize the common law tenancy by the entirety, a type of concurrent estate only available to married persons. Like a joint tenancy, a tenancy by the entirety conveys the right of survivorship to the co-tenants. Unlike a joint tenancy, however, neither tenant can break the tenancy by the entirety by unilaterally selling their portion of the property, and creditors of one of the tenants cannot collect against the property. States that recognize this form of joint ownership have created several different varieties, primarily regarding the types of actions a tenant by the entirety can take with regard to the property without their spouse's consent.